WO 2005/012818 discloses a method, a device and a system for heating by means of a gaseous medium comprising steam, said steam being produced from water, energy for heating the water being provided by burning a fuel, wherein the steam is mixed with exhaust gas from the combustion of said gaseous medium; and wherein said mixture is used for heating purposes, for e.g. cleaning and extracting oil. The mixture is also used for fire fighting.